Cylindrical aluminum pontoons generally have a main body made of a cylindrical member. Prior pontoons having a relatively long cylindrical member are constructed to have two or more cylindrical sections of aluminum welded together using circumferential welds intermediate the ends of the cylindrical section. The welds used to join the sections together are undesirable to performance and aesthetics of the pontoon.
The present invention is directed to a pontoon that uses a single section of aluminum to form the cylindrical section so as to avoid the need for circumferential welds intermediate the ends of the cylindrical section.
In a preferred embodiment, the pontoon includes a substantially cylindrical member having a length in excess of about 14 feet, no external circumferential welds intermediate the ends of the member, and being substantially linear along its length axis.
In another aspect, the invention relates to a pontoon boat having a pontoon and a deck buoyantly supported by the pontoon. The pontoon includes a substantially cylindrical member having a length in excess of about 14 feet, no external circumferential welds intermediate the ends of the member, and being substantially linear along its length axis.
In yet another aspect, the invention relates to apparatus for making a cylindrical member from a sheet material.
In a preferred embodiment, the apparatus includes a frame; first and second elongate rotatable rollers arranged and supported by the frame so that their length axis are substantially parallel in a vertical plane and spaced apart from one another in a horizontal plane, and a third elongate rotatable roller being arranged and supported by the frame so that the length axis of the third roller in the horizontal plane is between the length axis of the first and second rollers and the length axis of the third roller in the vertical plane is above the length axis of the first and second rollers. A drive system is operatively associated with each of the rollers for driving the rollers in a synchronized rotating motion. An anti-deflection system is operatively associated with the third roller and including a rigid member and roller contacting members connected to the rigid member for contacting desired portions of the third roller to urge the third roller so that it remains substantially axially linear when force is applied to it during manufacture of the cylindrical member.
In a still further aspect, the invention relates to a method for making a pontoon.
In a preferred embodiment, the method includes the steps of providing a sheet of aluminum having a length of at least 14 feet and encircling the sheet about its length axis using a roller having a length of at least 14 feet while simultaneously urging portions of the roller in a desired direction so that the roller is substantially axially linear.